A common technique for providing an under-floor surface for the subsequent erection of housing is to provide a leveled, poured concrete slab as the floor member upon which a building is erected. This technique is in particularly widespread use in the field of housing. Various techniques are known for fastening major structural members such as studs and walls to such a surface. However, the growing desirability of indoor, wall to wall carpeting as a covering for such a floor has led to the universal adoption of the technique of using small furring strips which are equipped to accept staples for holding and securing a carpet and which in turn are fastened to the cement slab.
Because these strips must provide an edge fastening method for a carpet but not change the level or provide bulk under the carpet they are of necessity quite thin, being typically three-eighths of an inch thick, made out of soft wood so as to readily hold the vertically extending staples which secure the carpet. In order to prevent destruction of the furring strip, the fastening means for fixing the strip to the cement slab must of necessity be of limited cross-section area, as the displacement of the strip by the fastening means would otherwise split the strip. Thus it is a universal practice to use a very small casehardened nail to fasten the furring strip to the cement slab.
Recent adoption of new types of cement have produced extremely hard cement slabs, that resist application of typical casehardened nails of usual shape. As a result it is common to find in typical furring strips that the application of driving blow to the fastening nail results in the nail being bent or destroyed rather than in the nail penetrating the concrete. It is typically found that the nail fails at the joint of the head and the body for hammer driven nails, and it has been observed for power driven nails that often the entire nail body is bent in a u-shape and the nail is simply reversed and driven back up through the furring strip. In either case, no fastening effect occurs to the cement and the attempt to fasten the furring strip to the slab is a failure.